Rotational Energy Vocabulary

Angular Velocity

The rate at which an object rotates or revolves around an axis, usually measured in radians per second.

Angular Acceleration

The rate of change of angular velocity, indicating how quickly an object speeds up or slows down its rotation.

Torque

A measure of the force that causes an object to rotate around an axis. It depends on the magnitude of the force, the distance from the pivot (lever arm), and the angle at which the force is applied.

Moment of Inertia

A measure of an object’s resistance to changes in its rotation, analogous to mass in linear motion. It depends on the distribution of mass relative to the axis of rotation.

Rotational Kinetic Energy

The kinetic energy an object possesses due to its rotation, given by 1/2Iw².

Angular Momentum

The rotational equivalent of linear momentum, given by Iw. It describes how difficult it is to stop a rotating object and is conserved in a closed system.

Axis of Rotation

The straight line around which an object rotates or revolves.

Angular Displacement

The measure of the change in the angular position of a rotating object, typically measured in radians.

Rolling Motion

A combination of rotational and translational motion, such that an object (e.g. a wheel) rolls without slipping. The point of contact has zero velocity relative to the surface.

Rotational Equilibrium

A state where the net torque acting on an object is zero, resulting in no change in its rotational motion (constant angular velocity or remaining at rest in terms of rotation).